Commit-ID: d75f152fc389cdd73a6c17f1247fce9052fd579c Gitweb: http://git.kernel.org/tip/d75f152fc389cdd73a6c17f1247fce9052fd579c Author: Feng Wu <feng.wu@xxxxxxxxx> AuthorDate: Tue, 9 Jun 2015 13:20:33 +0800 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Fri, 12 Jun 2015 11:33:52 +0200 iommu, x86: Avoid migrating VT-d posted interrupts When the interrupt is configured in posted mode, the destination of the interrupt is set in the Posted-Interrupts Descriptor and the migration of these interrupts happens during vCPU scheduling. We still update the cached irte, which will be used when changing back to remapping mode, but we avoid writing the table entry as this would overwrite the posted mode entry. Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> Reviewed-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: David Woodhouse <David.Woodhouse@xxxxxxxxx> Acked-by: Joerg Roedel <joro@xxxxxxxxxx> Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: dwmw2@xxxxxxxxxxxxx Link: http://lkml.kernel.org/r/1433827237-3382-7-git-send-email-feng.wu@xxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- drivers/iommu/intel_irq_remapping.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c index 68bce0a..3bcb459 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -1003,7 +1003,10 @@ intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask, */ irte->vector = cfg->vector; irte->dest_id = IRTE_DEST(cfg->dest_apicid); - modify_irte(&ir_data->irq_2_iommu, irte); + + /* Update the hardware only if the interrupt is in remapped mode. */ + if (ir_data->irq_2_iommu.mode == IRQ_REMAPPING) + modify_irte(&ir_data->irq_2_iommu, irte); /* * After this point, all the interrupts will start arriving -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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